How to Connect 2 4×4 Posts Together?

In case you are a newbie in woodworking, you may have to work with 4 by 4 sooner or later. You can connect 4×4 posts through half lap galvanized washers, bolts or even with steel plates. Again, you can use dowels in case of fencing. So, there are numerous ways to do it.

Connecting 2 4×4 posts together can be a complex task, but can be done smoothly if you know some tips and tricks. You just need to have a basic idea about what you can use, how you can use and what you cannot do. You can use a variety of techniques and tools to connect 2 4×4 posts together depending on your purpose of work.

In this article I will provide you a complete guideline, I will walk you through the steps to attach 2 4×4 posts without any flaw. So let’s dive in!

How to Connect 2 4x4 Posts Together

Can you Connect 2 4×4 Posts Together?

You can absolutely connect 2 4×4 posts together. In fact, you have variety of options in your hand. You can simply butt joint it by trimming the ends of the material so that it becomes square. But this is not that strong. Again, you can go for dowel or single lap etc. There exists other alternatives as well.

Before You Start

Every project will require a different joining method, so before you start you must think of the project that you are going to do. There is no rocket science to connect 2 4×4 posts together. Even what technique you need to apply will differ if the project is the same but in a different state. That is the reason you need to do some preliminary work before you start your task:

Check Building Code and Permits in the Region

You need to know the building code, guidelines, restrictions etc before you start digging fences. You need to ensure that when you are working on your roof or part of the home, it does not break the rules. 

Connect with fellow builders

If you are planning to do a project you can go to online meetings or seminars related to that type of woodworking. This will help boost your confidence and introduce you with ideas. 

Check the angle of joint

Recheck the angle in which you are connecting two posts together. Your angle will differ from the jointing method as well. 

Look up for instructions

If you tend to do any DIY project, always first check if it has any kind of guideline or restrictions on the internet.

Read Also: How to Fix a Sagging Double Gate

Reasons to Join 2 4×4 Posts Together

Reasons to Join 2 4x4 Posts Together

Due to many reasons you can think of joining 2 4×4 posts together. If you want to make a post longer, or make it short, repair a post or post-to-beam connections you need to join 2 4×4 posts together. Some reasons to join 4×4 posts are described below:

Extending Post

If you intend to add a privacy barrier or roof shelter, you may think of extending your fence. In this case you need to join 2 4×4 posts. You can also extend posts because of transportation or availability issues.

Repair Issue

Wood is a material that is erotic in nature. For this, repairing is your preferred option than rebuilding a wooden fence or deck. In this case you may need to join 4×4 posts.

Creating Long Skids

Joining 4×4 posts for horizontal use is a potential reason to join 4×4 posts together. You must be careful as a pull force affects differently than a downward force. 

Beam and Post Connection

In order to fasten beam to post or post to beam connection, you may go for using specialized brackets and support a butt joint.

How do you Connect 2 4×4 Posts Together?

You can connect 2 4×4 posts together through numerous processes. Some of them are discussed below-

Half Lap Joint

This process is also known as single lap or shiplap joint which is basically used to join wood into longer lengths for more than a millennium. In a half lap, a joint overlaps by half the thickness of the pieces being joined so that it becomes less visible. This type of joint look like a chair seat with a high straight back.

Careful and accurate measurement of cuts are vital in this joint.

To make a half lap joint, first measure to find the centerline of two pieces. Mark two sides and determine where the cut will end. Then measure from the end and identify the desired length of the cut and mark it on both sides. As the depth is always half, the length depends on use and compliance with building code of that area. A basic hand saw, hammer and chisel is all needed for a half lap joint.

Stronger joint both in case of horizontal and vertical joint. Easy Application Can resist crush or bending.Time consuming Process Cut should be proper for maintaining accuracy. Requires saw skill.

Rabbet Joint with a Steel Plate

When working on a heavy-duty project you may use a rabbet joint with a steel plate to reinforce the joining. Rabbet joint alone cannot withhold a roof structure, that is why a steel plate is needed to add with the rabbet joint in order to reinforce it. 

First you need to cut a 24 inch rabbet joint, then use steel plates to reinforce the joints. Lastly, secure everything with four long belts.

Make strong corners Easy to build Useful in case of cabinets, drawers and box like structures.Not easy to hide the joint Not flexible, once done, cannot change it. Cannot work with curved wood edges. 

Using Dowels or Connecting Rods

This is a traditional way of connecting 2 4×4 posts together. First you need to drill almost entirely through two pieces of wood. Then a dowel or connecting rod has to be inserted in the hole. Next you will have to use wood glue so that it does not go out from its place. Tap into place with a hammer if needed. 

Cheap joint Good for horizontal connection.Difficult to use in a vertical connection Sometimes may produce a shear fault in the joint.

Butt Joint with Hollow Pipe Insert

A hollow 10 to 12 inches butt is used in this process. First a hollow is inserted into a hole drilled vertically into the center of the ends. The 2 4×4 posts butt is inserted. Lastly, a pipe is inserted into the hole and secured with glue or adhesive.

Strengthens lateral resistance Good for vertical joint Easy to conceal the joint.Needs special tools Sometimes post may bend or curve in alignment Weakens horizontal strength of wood.

Tips to Make Sure to Get a Solid Bond

You can follow some tips and techniques in order to ensure to get a solid bond in your joint such as-

  1. Go for steel Plates: You can always consider choosing steel plates for any kind of joint as steel plates are easy to find, help reinforce the joint and keep it in its place.
  2. Think of your purpose: Try to prioritize your purpose of joining. If you want your joint to be strong, you should not think about aesthetics first. Again, if you want joining be such that it looks like a part of furniture piece, you need to choose elements that are easy to conceal.
  3. Work with your familiar tools: If you are good with half laps, use that. If you are good with butt joints, go for that. 
  4. Use a good quality glue: Without a good quality glue, chances of displacement of joint is high. So this part is crucial.
  5. Think of hurricane-galvanized steel reinforcements: If you live in an area that is prone to hurricane, you should think of using hurricane-galvanized steel reinforcements. This can be an essential part according to the building code. 

Strongest Way to Connect 2 4×4 Posts Together

The strongest way to connect 2 4×4 posts is to half lap but it should be glued, plated and bolted. When you are working on posts under load or working in a limited space, half lap is your go to joint. Again, this is the easiest way to cut as well. Cutting a half lap on a fixed post is easier than all other cuts.

Moreover, maintaining accuracy is possible.  A glued, bolted tapered scarf joint is stronger than half lap and probably the strongest. But the problem is it is not easy to cut in a limited space. In addition, accurate sawing is crucial. If the joint is poorly sawn, the joint will not be strong enough.


What is the weakest wood joint?

A butt joint is the weakest wood joint as it is a very simple technique. Only two pieces of materials are connected at their end. 

What’s the strongest wood joint?

Half lap with properly glued and bolted, is the strongest wood joint of all. Again it is most suitable for all environments. Although tapered scarf joint is strong as well, its accuracy is difficult to maintain

Is wood glue stronger than screws?

Definitely wood glue is stronger than screws. Screws only grip the wood in a specific location but wood glue can grip the wood across the joint. 

Do wooden posts rot in concrete?

Yes, wooden posts can rot in concrete. If concrete is being poured on the wooden fence, it may rot or accelerate the already existing rots. But this problem can be solved if you pour it properly. 


There are numerous ways to connect 2 4×4 posts together. Among them, half lap or single lap is the best one. This joint is convenient for the beginners as well as professional workers. In order to reinforce your joint you must add high quality wooden glue or bolts with the joint. Again you can go for other types of joints based on your preference.

Now you know how to choose a type of joint to connect 4×4 posts together. With all the tips, tricks and hacks you are all set to connect you fence in your indoor or outdoor!

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Manuel Elmad

Manuel Elmad has always been interested in technical things. When he was just a kid, he worked in a mechanical shop and learned all about the inner workings of electronics and machines. This sparked his thirst for knowledge and led him to pursue a career in this field. For the past 8 years, He has been working as a technician and loves to learn new things and also helps others to learn. In his spare time, Elmand likes to strike on the keyboard for spreading his knowledge and go hiking with his friends.

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